Unusual displacement hull forms for higher speeds

Article type: Research Article

Authors: Boericke Jr., Harold

Abstract: A sharp increase in the wave resistance has limited speeds of full-bodied surface vessels to a practical maximum which has sometimes been called the “wave barrier”. Two approaches towards increasing the top speed of displacement type surface ships are investigated herein. The first approach is that of keeping Froude number constant and increasing length. The second approach, involving operation at high Froude numbers, is emphasized. This involves a study of minimum wave resistance at Froude numbers greater than 0.35. Principles for minimizing wave resistance are proposed. The wave resistance of certain elementary shapes is reviewed, and several forms likely to have a minimum wave resistance are discussed with reference to the principles proposed, and with reference to operation in rough seas. Heavy displacement type hull forms exist which “break the wave barrier” reaching Froude numbers greater than 0.9 (speed-length ratios greater than 3.0), thus multiplying their speed capabilities. The form characteristics which make for a higher speed may, within limits, also make for a maximum propulsive efficiency and a minimum motion in a seaway. The concept of increasing depth instead of increasing length in order to increase speed and seaworthiness is also briefly investigated.

DOI: 10.3233/ISP-1959-65802

Journal: International Shipbuilding Progress, vol. 6, no. 58, pp. 249-264, 1959